1. Field of the Invention
This invention relates to a method of cutting a glass article along a planned cutting line by thermal stress.
2. Description of the Related Art
A glass article cutting method of the type mentioned is already known. An exemplary one of conventional glass article cutting methods is disclosed, for example, in Japanese Patent Laid-Open Application No. 1-167248. According to the conventional glass article cutting method, a nichrome wire is laid along a planned cutting line on a surface of a glass plate, and electric current is supplied to the nichrome wire while mechanical stress is applied to the glass plate in a direction perpendicular to the planned cutting line, whereafter water is dropped to cause water drops to stick to an end face portion of the glass plate so as to effect thermal stress cutting of the glass plate.
However, according to the conventional glass article cutting method, a nichrome wire which is a ready-made wire stock is employed, and the nichrome wire is laid and energized on a surface of a glass article. Accordingly, the conventional glass article cutting method is disadvantageous in the following points.
First, while there is no trouble when the planned cutting line is a linear line, it is difficult to cut a glass article along a curved line particularly of a free configuration.
Further, the cross contactness between a surface of a glass article and a nichrome wire is low, and consequently, the thermal efficiency is low.
Furthermore, when there is a concave or convex portion on a face of the glass article, a nichrome wire is spaced away from the face of the glass article at the concave or convex portion, and consequently, the glass article cannot be cut at the portion.
In addition, it is very difficult to contact a nichrome wire with a surface of a glass article having a complicated profile such as, for example, a three-dimensional profile. Accordingly, the glass article cutting method cannot be applied well to cutting of a glass article having a complicated profile.